This invention relates to a system for accumulating and storing heat energy in the form of superheated water. It may be used, for example, to recover heat energy which ordinarily might be wasted from nuclear or more conventional steam generating systems as are commonly employed by public utilities, industrial plants or the like. In this regard, it is not uncommon for such facilities to waste substantial quantities of energy by discharging heated water into rivers or into the atmosphere. It is among the primary objects of the invention to provide a system in which such heat energy may be stored without reducing the output (for example, electrical production) of the generating station during normal peak hours of consumption.
The invention includes an enlarged container which may be formed directly in the ground by excavation. The excavation is divided into a pair of upper and lower compartments by a diaphragm which extends in a substantially horizontal plane. The diaphragm is heat insulative and is impermeable. The lower compartment is connected to the heat source (the steam generating plant) to receive superheated water from the heat source. The upper compartment, which is exposed to the atmosphere, is filled with a substantial mass of water which applies a substantial and uniform pressure to the diaphragm and, therefore, to the super-heated water in the lower compartment to preclude the superheated water from boiling and to maintain it in a superheated state. The superheated water from the lower compartment is connected to a load or heat sink circuit by which the superheated water is pumped from the lower compartment to a heat exchanger to heat a working fluid which can be pumped to desired locations, such as urban heating systems. The system is arranged so that the mass of water employed in the superheating, storing and heat discharging circuit is constant.
The diaphragm is attached to the peripheral wall of the excavation by a flexible connection which maintains the isolation between the upper and lower compartments. Means also are provided to maintain the relatively large diaphragm in a substantially flat, horizontal configuration and this includes a plurality of ballast weights located at or attached to the upper surface of the diaphragm at a plurality of locations. Each of the ballast weights is connected by a cable to a partly submerged float which floats at the upper surface of the water in the upper compartment. This resists any tendency for the diaphragm to deform from its substantially horizontal flat configuration.
It is among the objects of the invention to provide an improved system to recapture and store heat energy from a steam generating station or the like.
A further object of the invention is to provide a system of the type described in which the heat energy is stored in the form of superheated water.
Another object of the invention is to provide a system of the type described in which the superheated water is stored in an enlarged excavation which is separated by a diaphragm into upper and lower compartments and in which the superheated water is stored in the lower compartment.
Another object of the invention is to provide a system of the type described in which the superheated water is circulated in a closed circulatory system having a constant mass of water.
Still another object of the invention is to provide a system of the type described having means for stabilizing the diaphragm to maintain it in a substantially flat, horizontal configuration.